Shear stress augments the enhanced adhesive phenotype of cells expressing the Pro33 isoform of integrin beta3

Adhesion of platelets to the exposed extracellular matrix proteins at sites of vascular injury is partly regulated by the local fluid shear stress. Because the Leu33Pro (Pl^A) polymorphism of integrin β₃ confers only a modest increase in adhesion under static conditions, we used CHO and 293 cells expressing the Leu33 or Pro33 isoform of β₃ in flow chamber experiments to test whether shear forces would alter the Pl^A adhesive phenotype. We found that shear force augmented the Pro33-mediated enhanced adhesion to fibrinogen. This Pro33-dependent enhancement was aspirin-sensitive and was also observed on immobilized von Willebrand factor and cryoprecipitate, but not fibronectin. Thus, shear stress enhances the adhesive phenotype of the Pro33 cells to multiple physiologic substrates.